Could Wormholes Exist?

In science fiction, wormholes are hyperspace subway tubes linking one part of a galaxy directly to another, distant point. But could they actually exist? To find out, we talk to theoretical physicist Ron Gamble https://www.theoreticallydrgamble.com/, who says wormholes aren't just a matter of science fiction — and they have big implications about the shape of space itself. Want to hear about more hypotheticals physicists have to confront in their work? Email us at [email protected] mailto:[email protected] — we might turn your idea into a whole episode! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave http://plus.npr.org/shortwave. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:00Speaker 00

  This message comes from Capella University. That spark you feel? That's your drive for more. Capella University's FlexPath learning format lets you earn your degree at your pace without putting life on pause. Learn more at capella.edu.

• 0:15Regina Barber?

  You're listening to Short Wave from NPR. Space. I love it and the things inside of it. Us, of course, stars and galaxies I studied, and I even love the other cool hypothetical stuff that mostly lives in science fiction, like wormholes.

• 0:35Regina Barber?

  Wormholes are a funky, but possible, solution to Albert Einstein's famous equations for the theory of general relativity. These theoretical cosmic portals can shorten a trip from hundreds of light years to minutes. Wormholes have been a mainstay of transportation in movies like Interstellar

• 0:51Speaker 02

  That's it. That's the wormhole.

• 0:54Regina Barber?

  And TV shows like, my favorite, Star Trek.

• 0:56Speaker 02

  The aliens who live in the wormhole, as you call them.

• 0:59Regina Barber?

  Which Ron Campbell says is not far off from how scientists think about these wormholes.

• 1:03Speaker 03

  It's very much like a bridge. You can do this thought experiment yourself. You take a sheet of paper, you fold it kind of like in half, and you poke a pencil hole right through the middle. And that is essentially a wormhole. It connects two points in space and time together.

• 1:20Regina Barber?

  Ron's a theoretical physicist, and he wrote his PhD on funky solutions to Einstein's equations for general relativity, like wormholes. Basically, he did this by studying spacetime, the four-dimensional existence we all live in. It includes three dimensions of space and one dimension of time moving forward as that fourth dimension. And general relativity talks about how spacetime itself has a shape to it.

• 1:48Regina Barber?

  A shape that is distorted by all of the wonders inside of it. All the beautiful stars, planets, galaxies, black holes. Their distortion of spacetime is gravity. And if you push that gravity to its extreme, you get black holes. And some physicists theorize that white holes could also exist. And that would be the opposite to a black hole. They'd push out matter instead of consuming it. And the thing that could connect them is a wormhole.

• 2:18Regina Barber?

  But scientists have never seen one. And as a lifelong Trekkie, I have long wanted to know, could we ever? Or are wormholes purely science fiction?

• 2:29Speaker 03

  I think, according to the physics, there is a non-zero chance that we could find a wormhole.

• 2:34Regina Barber?

  So you're saying there's a chance?

• 2:35Speaker 03

  I think if we find a wormhole, that means someone else created it.

• 2:41Regina Barber?

  So today on the show, wormholes, the geometry of spacetime, and how, to a theoretical physicist, if the math checks out, you can't rule it out. I'm Regina Barber, and you're listening to Short Wave, the science podcast from NPR.

• 3:03Speaker 04

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• 4:05Regina Barber?

  OK, Ron, let's start with hard stuff today. Honestly, because like, before we can talk about like, fun wormholes, we kind of need to talk about Einstein's theory of general relativity. And this seems like kind of jargony, but it has been talked about in movies. Can you help us out? Can you summarize the theory of general relativity?

• 4:23Speaker 03

  General relativity is, in a nutshell, it is geometry. Cubes, we're thinking about spheres, cylinders.

• 4:31Regina Barber?

  Pyramids.

• 4:32Speaker 03

  Pyramids, tetrahedrons, pick your favorite geometry.

• 4:36Regina Barber?

  Yeah.

• 4:36Speaker 03

  But there is a specific set of dimensions where general relativity works and it does not. We have found that in dimensions of three, so we're talking about X, Y, Z, up, down, left, right, and the added dimension of time, right? Physics tends to work, or our reality tends to be well behaved, like a well behaved child, right? But the difference here is, is that general relativity describes these geometries using curved surfaces or curved spacetime. How does event A and event B relate to each other?

• 5:18Speaker 03

  Through a curved surface, which is just a webbing of multiple events in between the two. So you can think of-

• 5:28Regina Barber?

  Like a planet going around, like Earth going around the sun.

• 5:31Speaker 03

  Earth going around the sun, you know, if the Earth has mass, the sun has mass, the Earth is actually going to be more attracted to the sun. It will, they both will pull on each other, but the Earth sits in the curved surface that the sun creates, and that's why we're being attracted to it. That is, that's general relativity in a nutshell.

• 5:51Regina Barber?

  Yeah, like, like the things at the mall where you put the coin in. That's what I would always say to my students.

• 5:56Speaker 03

  It is a perfect example.

• 5:58Regina Barber?

  Thank you, thank you. Okay, space is curving, and one consequence of like that curving is wormholes. Like, can you describe a wormhole?

• 6:08Speaker 03

  So very plainly, I would kind of describe the wormhole like a subway tube. So you get in on one, on one side. So let's say you're getting in on Penn Station in New York, and you get off at Grand Central. But the in-between, right? So just like the subway's going underground, the wormhole is kind of like what we call like a hyperspace. So you're not actually, you know, traveling like if you were on the surface. You're kind of tunneling through spacetime itself, and then coming out on another side. So it's a, it's a very weird, kind of like, physical attribute.

• 6:47Regina Barber?

  Okay. And like we said earlier, right, like the tunneling of a wormhole is this like connection from a black hole that consumes matter to this like theoretical white hole that pukes out matter somewhere else in space.

• 6:58Speaker 03

  Yeah.

• 6:59Regina Barber?

  This image is like hard to reconcile with like the classic way teachers describe spacetime, like this 4D stretchy sheet, like think of this trampoline material with like a bowling ball in the center and that's like a star in spacetime. Like, how do you feel about this like stretchy sheet metaphor?

• 7:18Speaker 03

  I think the rubber sheet analogy is a scam. I think it's because it doesn't actually, so again, like our definition of general relativity, it doesn't give you the accurate description. This is an introductory to curved surfaces and things like that.

• 7:34Regina Barber?

  Yeah.

• 7:36Speaker 03

  But it doesn't actually show you the dimensionality of space and time.

• 7:40Regina Barber?

  Okay.

• 7:40Speaker 03

  So instead of using the rubber sheet, I tended to use putty. You can ball it up into whatever shape you want and then deform it and curve it and spin it around. And now you're getting all of the physics that's kind of involved in the different configurations of space and time, which is general relativity.

• 8:00Regina Barber?

  Yeah. And maybe like another complication, like for people who have heard it, is this idea that black holes are like potholes in the in the fabric of spacetime. And we've said it before on this show because it's a great way for scientists to convey this like huge amount of gravity. But in a conversation about wormholes, maybe it's too simplistic. It's better to think about a black hole as a sphere.

• 8:22Speaker 03

  This is why, again, I say that the the rubber sheet analogy is a scam because we assume that black holes are actually holes in space. They're not. They're spheres. And so they're actually squished spheres because they're rotating, right? And so

• 8:38Regina Barber?

  Like in Interstellar, that artist

• 8:40Speaker 03

  Just exactly like in Interstellar. Yeah. So it's a great image. And we've seen these. We've taken pictures of black holes in galaxies and seen that they, these are circles, these are spherical objects.

• 8:49Regina Barber?

  Wow.

• 8:50Speaker 03

  And so then the next thing would be, okay, for a wormhole. What would it look like if I entered a wormhole from one side? Would it be a hole or would there be just some tube sitting in space? Well, no, it would be one sphere connected to another sphere.

• 9:07Regina Barber?

  Okay, I love that image. It's like, it's like a dumbbell. But why are people so resistant to like wormholes existence? Like, why would we not see one in nature?

• 9:18Speaker 03

  So one of the requirements for a wormhole is you need exotic matter.

• 9:21Regina Barber?

  So like not regular matter that like clumps to itself?

• 9:24Speaker 03

  Yeah, so you need matter that's pushing out. You need matter to keep the wormhole, so to speak, open. And that means that that is matter that's not trying to clump together like our matter that we know of. You know, if you drop a ball, it's going to fall towards the earth. But this matter, if you drop a ball, it will repel, it will go in the opposite direction. And so

• 9:50Regina Barber?

  It's like anti-gravity.

• 9:52Speaker 03

  It's like anti-gravity, but in a sense that we would need, you know, we are very weird atoms or something to hold the wormhole together. Hold it together and keep it open. So you need a force, you know, if you will, to push against the fabric of spacetime to hold it open so that you can go through.

• 10:13Regina Barber?

  Right.

• 10:15Speaker 03

  The other thing is, is that you need kind of like, so to speak, a, I would say like a fake extra dimension so that you can travel from point A to point B. If point A is in four dimensions and point B is in four dimensions, how do you get from A to B if you only have four in between? Right? So you would need kind of like an extra dimension to travel through and then fall back down into four.

• 10:41Regina Barber?

  So like the wormhole itself is a fifth dimension?

• 10:44Speaker 03

  It could have a fifth dimension, right? So that you can have the ability to travel through it. And this is where we get the idea of like hyperspace.

• 10:54Regina Barber?

  What?

• 10:55Speaker 03

  Star Trek, Star Wars, it's all in there. They went to a hyperspace. That was an extra dimension larger than the one that they actually lived in.

• 11:02Regina Barber?

  Wow.

• 11:03Speaker 03

  To travel from point A to point B. Yeah.

• 11:05Regina Barber?

  So I remember reading that, like you were saying, you need this like weird matter or energy to keep wormholes open because they're going to collapse otherwise. So if we were to detect a wormhole, someone from like a different alien civilization would have had to make it.

• 11:20Speaker 03

  Somebody, yeah.

• 11:21Regina Barber?

  Why would somebody have to make a wormhole? Like civilization?

• 11:25Speaker 03

  Yeah, it's entirely based on our understanding of our, our reality. And so according to physics and the standard model of everything, right? We have not seen any possible evidence or any clues the way matter behaves to suggest that there would be exotic matter without it escaping to use for us specifically that wormhole. So that is why, you know, most people, if you ask them, well, what, what happened if we found a wormhole? That means, well, we found evidence of another civilization.

• 11:59Regina Barber?

  Wow.

• 12:00Speaker 03

  Or we put it there from the future, right? Which is another possibility. But.

• 12:07Regina Barber?

  I love talking to theoretical physicists, like anything's possible.

• 12:11Speaker 03

  Anything, it could be. But all in all, it, it does suggest that something created it and not, and, and not it being kind of naturally occurring because it seems unnatural to exist.

• 12:24Regina Barber?

  So we're talking about all these like possibilities, right? You would have to find this exotic energy, this exotic matter. But like, so what is the main skepticism? When, when you're talking to astronomers, when you're talking to other scientists, what is main reason why wormholes is something that's kind of still in like the outlier research topics?

• 12:48Speaker 03

  Yeah. Um, it's mainly because we can't test it. So it's, it's still kind of looked at as like a science fiction. I wouldn't say it's fringe because we, we have, you know, real mathematical solutions that we can, you know, kind of simulate, if you will. But in terms of something being viably testable, because that's the scientific method, we have to recreate it, you can't test for a wormhole. You can't even create one experimentally. And so that is, I would say, the pushback or the, you know, the grief against wormhole research is that, you know, this is, it seems like it is decades, if not centuries, of technology ahead of us.

• 13:32Speaker 03

  And so then the question is, well, why would you study wormholes? Well, I would say, why would you not? Why, why, why not? That is, you know, that's kind of giving us another clue about how our universe could behave. And then, given the fact that we've only seen 5% of our observable universe, the other 95% could have wormholes in it, and we've just not looked hard enough.

• 13:57Regina Barber?

  For you, why is it so important to not rule out these mathematical solutions to general relativity?

• 14:03Speaker 03

  Because at one point, space travel was fiction. At one point, the cellphone was fiction. You know, the computer was fiction. Quantum mechanics was fiction. So I, I look at, you know, all of these theories, and this is kind of my motivation as a theoretical physicist, is that someone has to work on these problems, but do it creatively to generate the advancements in technologies decades later. And so that is why, you know, I work on black holes and jet physics and things like that, and why one would work on wormholes, because we need somebody to solve these very, very fundamental or basic problems and do it creatively and innovatively, right? So that we can have something to advance

• 14:47Speaker 03

  our technologies to later on.

• 14:53Regina Barber?

  Ron, thank you so much for talking with us today. I've become slightly more hopeful for the existence of wormholes.

• 15:01Speaker 03

  That's great. Thank you for having me. This was fantastic.

• 15:06Regina Barber?

  This episode was produced by Burleigh McCoy, edited by our showrunner, Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineer was Jimmy Keely. Betsy Onovin is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave from NPR.

• 15:35Speaker 04

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